Dr Tom Little, one of 10 people killed by militants in northern Afghanistan, had spent more than 30 years working in the country, often in harsh and remote areas.
Little, a senior ophthalmologist from Delmar, New York, led the team of nurses, doctors and logistics personnel murdered in the attack. He was expelled by the Taleban in 2001, after eight Christian Aid workers were arrested for allegedly trying to convert Afghans to Christianity. He returned with the Christian organisation International Association Mission (IAM) soon after the Taleban was toppled in November 2001.
As a senior member of IAM working with the Noor Eye Institute, Little trained the former Afghan Foreign Minister and presidential candidate Dr Abdullah Abdullah.
He supervised eye hospitals as well as smaller clinics. IAM has worked in Afghanistan since 1966, longer than any other NGO, and treats a quarter of a million Afghans every year.
His team trekked from village to village over two weeks in Nuristan Province, providing specialist eye treatment and healthcare to around 400 people before last week's attack, said IAM's director, Dirk Frans.
Frans lost contact with Little last Thursday, but his death and those of the others were not reported until Saturday, when an Afghan member of the team who survived managed to call.
The Taleban yesterday claimed it had shot the "foreigners" because they were "spying for Americans" and "preaching Christianity".